


Supergirl is a Tentacle Monster

by rowename



Category: Supergirl (TV 2015)
Genre: Alien Biology, Consentacles, F/F, Midvale (Supergirl TV 2015), Shameless Smut, trypophobia - brief mention, why not?
Language: English
Status: Completed
Published: 2019-06-22
Updated: 2019-06-22
Packaged: 2020-05-16 04:57:34
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,126
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19311082
Author URL: https://archiveofourown.org/users/rowename/pseuds/rowename
Summary: In which kryptonian biology means Kara needs to get laid in her pre-Supergirl days, and can’t do much about it because it’s harder to pass for human during sex. Good thing there is one person who knows she’s an alien and might be able to help her through it.Also, tentacles.





	Supergirl is a Tentacle Monster

**Author's Note:**

> I'm bored with writing sensible stuff.

Alex wasn’t sure what she’d expected. Kara had skittered up to her room fairly regularly for the last few weeks, and Eliza was getting a bit worried; she’d anticipated unexpected challenges to raising an alien, but nearly a decade had passed without much of a problem.

Until this. So Eliza had asked Alex to go up to Kara’s room, make sure she was ok. Alex had put up her usual fuss, complained about always being expected to look after Kara, but still gone up without much resistance.

At first glance nothing seemed strange. Then again, Kara had super hearing and speed, she’d had all the time in the world to hear Alex coming and make things look normal. She’d rolled over in bed, pulling the sheets up to her stomach and looked as though she was reading. Only the faint flush in her cheeks gave any indication something was amiss.

“Kara?” Alex said.

“Alex! Hi!” Kara said, her voice a little too high to be normal. “Do you need something?”

“What’s wrong?” Alex said.

“Huh? Nothing’s-”

“What’s wrong?” Alex said, again, making it palpably clear she wasn’t buying Kara’s act.

She walked over, sitting on the side of Kara’s bed and meeting her adoptive sister’s eyes unblinkingly. Kara’s flush deepened.

It was a few seconds before Kara answered, wringing her hands together.

“It’s a little, uh…” Kara said.

Her eyes dipped down. Alex followed her gaze to the sheets, or more specifically, what was beneath them. Eyes on Kara’s covered crotch, and recalling her sister’s evident embarrassment, the problem quickly became obvious.

“Alien sex stuff?” Alex guessed.

Kara squeaked.

“Well…” Kara said. “It’s sort of… complicated. Every few years there can be a build-up if we don’t… release, especially now I’m matured, so it’s kind of a… lot to…”

“You can’t just… take care of it?” Alex said slowly.

She flushed a little herself, not entirely able to believe she was actually having this discussion with Kara.

“Um,” Kara said.

“Or find some random,” Alex said. “No one’ll judge.”

“I can’t… really…” Kara said. She hesitated. “I’m not exactly human.”

“Oh. Oh!” Alex said. “They’d notice?”

“I… probably,” Kara said.

“So take care of it yourself then,” Alex said. “I… humans do it all the time. Just hands or something.”

“That’s not really…” Kara said.

It was getting harder and harder to talk in full sentences. Ok, her sister needed to get off and apparently alien genitalia made it tricky, it wasn’t exactly an exchange she was prepared for!

Still, she’d gotten close to Kara, and judging by Kara’s flustered hurrying to her room each day, and her increasingly pained expression, it was a legitimate problem. Alex glanced down at the covers nervously.

Ok, teaching her sister how to masturbate had never been on her to-do list but if she had to…

“Just show me,” Alex said.

Taking a breath, Alex pushed down the sheets. Underneath Kara was bottomless, smooth bare legs under the duvet leaving little doubt as to what Kara had been unsuccessfully trying before Alex had come in. And at the join of her legs was a slit; ok, it was a little _off_ compared to a human’s, almost featureless and pale, but it wasn’t too different.

And then something pushed out.

It was definitely flesh-coloured, maybe tinged a little more with red than the rest of Kara, but definitely part of her. About as wide as a certain body part Alex really didn’t want to be thinking about just them, it wriggled and squirmed and _kept going_ , sliding out from her sister’s depths and swaying gently between them.

Alex stared. She was so captivated that she almost missed as another started to emerge from the gap between Kara’s legs, and another, and…

Alex swallowed.

“Huh,” Alex said. “Ok. Not… what I expected.”

Her sister had tentacles. Somehow that felt like something she should have spotted, even if they were normally hidden away. How did all this even fit?!

Curiously Alex reached out, her hand shaking slightly, and touched the closest. It was warm. It reacted to her touch, twitching, feeling like skin (maybe slightly coarser), hot and yielding, and Kara suddenly moaned on the bed.

Remembering just what part of her sister that was, Alex hastily snatched her hand back.

“D-don’t,” Kara said, blushing. She continued breathlessly. “It’s… I can’t really… with anyone who isn’t kryptonian.”

Alex was still staring at the squirming fronds. That was one, two, three, four, five… Wow.

“Alex!” Kara said. “I know it’s not many, but you don’t have to stare!”

Alex blinked.

“Not many?!” Alex said.

“Oh! Oh, right, you wouldn’t…” Kara said. “Kryptonians… grow more as they get older. I’ve only just started… so… Is it ok?”

“I… yeah, yeah, sure,” Alex said. “I’m just seriously side-eyeing Lois Lane now.”

“Oh! No, Clark wouldn’t have these,” Kara said. “He’s a guy. He would’ve had no trouble when he was growing up. They get…”

Kara paused for a moment. She tilted her head, struggling to think of the word.

“It’s kinda like honeycomb,” she said. “Lots of little-”

“Alright, alright, enough detail!” Alex said. “What about you? You said you can’t just…”

“I need all of them to be… stimulated,” Kara said. She reddened. “It’s not something I can really do alone. There’s a lot to…”

Alex stared. Half a dozen tendrils swayed, looking almost relieved to be out in the open air.

She wasn’t sure what she’d expected to be the problem, but this definitely wasn’t it. Her sister looked at her, face a perfect study in innocence and self-consciousness as horny tentacles emerged from her nether regions.

“So…” Alex said slowly. “You need to… get off so it stops bothering you?”

“Um, yeah,” Kara said. “I don’t know how I’m meant to though. On Krypton there were these things that could help with it, just swallow a pill to trigger a… well it ended it.”

“How often do you need it?” Alex said.

“Not often,” Kara said. “It takes years to build-up. A good release now and I won’t need to worry about it for a while.”

“Alright,” Alex said.

She took a breath, still staring. On one hand, she was certain what she was thinking was a terrible idea. It was stupid, those were _tentacles_ , Kara was her _sister_ , she was hardly experienced with the vanilla stuff far short of all this, those were _tentacles_ …

Then again she couldn’t quite stop looking at the swaying, wriggling, hot tendrils, to say nothing of Kara’s expression.

“Alright,” Alex said. She swallowed again. “So if I help you, this one time, will that…”

“Help- Alex!” Kara said. Her voice went high. “You want to…”

“Well you need someone, and I’m the only person who can know, unless you want to ask mom-”

“N-no, happy with you,” Kara said. “You’re sure?”

Alex hesitated. It was slightly embarrassing just how quickly she’d gone from seeing the tentacles to agreeing to bang them, but she _really_ didn’t want to dwell on those thoughts. Instead she nodded and tried not to seem overeager.

“Sure,” Alex said. “So. Uh. How do we do this?”

“Just… relax,” Kara said. “I think that’s important. Otherwise, um, say if it’s too much.”

“Don’t rush,” Alex said.

She faltered, then nodded, and the tentacles moved.

They slid through the air with astonishing ease, Kara either having perfect control of the… things, or their automatic reactions being natural enough. They hesitated a little distance from Alex’s waiting body.

Tentatively Alex reached out again, moving to hold one of them. It quickly jerked back, then darted closer, curling around her wrist before resting against her palm. Alex raised her eyebrows, looking over to Kara while idly wrapping her fingers around the friendly tentacle.

“Instinct! Sorry,” Kara said. “They kind of like to… is that ok?”

“Very,” Alex said, eyes dark.

She reached out with her other hand, a tentacle coiling around her wrist again before offering itself to her palm, controlling where her arms were positioned even as she gently stroked the two.

Kara’s breath came faster, and the remaining tentacles shuddered.

A thicker one neared Alex’s mouth; she wetted her lips, parting them to accept it, only for it to back away. It slid down, angling itself, and for a moment she thought it was going to slide beneath her waistband.

Instead it angled up, and Alex’s breath caught in her throat the moment she felt the heated skin against her abdomen. It slid up under her top, her body tingling where it touched her, before slipping through her cleavage and out the neck of her top. It coiled once, twice around her throat on instinct before again offering itself to Alex’s lips.

That time she was struggling to engage her brain properly. Eventually she remembered to open her mouth, and the sound of Kara’s low gasp as she ran her tongue down the heated length was like music to her ears.

“That’s… that feels really good, Alex,” Kara said.

Somehow she’d stopped being weirded out the first moment she’d touched a tentacle. It just felt so unreal, one moment checking on her sister, the next _tentacles_.

Kara’s reaction brought her back down to earth; these weren’t just abstract things, they were, somehow, part of her sister. Kara felt what she did them, her hands were stroking Kara, her lips wrapped around Kara…

She felt the tendril in her mouth slide in, hitting the back of her throat before withdrawing. It did feel like skin, more or less, though maybe it was a little hotter, a constant pleasant simmer making extra sure she couldn’t forget where it touched her.

It was hard to not wonder at how long they were, at just how much Kara hidden away. She was at her mercy, and somehow that made Alex suck with all the more keenness.

Her heartbeat quickened, arousal catching her off-guard with its intensity, and that was before another tentacle again approached.

“Is it ok if I…” Kara said, panting slightly. “I need all of them to be…”

“Mmf!” Alex said. The tentacle in her mouth withdrew for a second. “Please! Kara, please!”

A tentacle slid up her pantleg. It wrapped around her leg, not bothering nor needing to undress her, coiling first around her ankle, then knee, then thigh, then reaching her underwear.

It dragged a low moan from Alex’s lips as it prodded experimentally, before it found its way inside.

The tentacle around her throat tightened slightly, angling to pull Alex’s head back; the tip in her mouth started to move, its excitement mirroring that of the one that had just reached her entrance.

It felt oddly pleasant. Not just the sheer intensity of the sex part of it, but the heat of all those limbs coiled against her, bizarrely comforting. She could feel it wrapped around her leg, against her chest, around her wrists, as if reminding her that it was there.

Not it, as Kara’s low moan made clear. Her. It kind of figured that even if Kara was a tentacle monster downstairs, she’d still be a cuddler.

Her hands still stroked, fingers grasping the admittedly phallic tendrils all the more urgently as she felt herself lay back, arms trembling. She writhed under the four tentacles, too overwhelmed even to marvel at how easily the most recent slid into her soaked depths.

And then she felt another spiralling up her other leg. It felt thinner; if Kara was right about kryptonians growing more, maybe it was her youngest, width more like a finger than anything else.

She felt it ascend, around her shin, her hip, then passing the other still moving into her to slide between her cheeks. Alex’s eyes widened.

“Mmf!” Alex said.

It stilled; it still took a second for the tentacle in her mouth to pull back, shaking slightly.

Alex refocused, trying to take in the real world again. Kara was sweating; she still sat where she was, making no effort to move the rest of her, but still shivered slightly from the sensations greeting the mass emerging from between her legs.

“S-sorry!” Kara said, her voice strained. “I just… I need one more, it’s the last one, I need all of them…”

“Just, ah! Could’ve done with a little warning,” Alex said.

She hesitated. Ok, anal wasn’t something she’d expected, but neither was kinky tentacle sex with her sister. Somehow it seemed less taboo if a tentacle did it.

“Just be slow,” Alex said.

“Really?” Kara said. She nodded eagerly.

Alex smiled, and whatever she was about to say was quickly muffled as a tentacle returned to her mouth.

And then the other slid inside her, claiming the last part of her. Alex arched her back, a muffled moan sending shivers down the tendril in her mouth, unable to deny the thrill that it sent through her.

It was like all the world had faded away. Nothing could compare in intensity to the burning hot tentacles wrapped around her, holding her, sliding inside her…

Every bit of her.

She wasn’t sure if she gave an indistinct scream, or if she was shouting out Kara’s name, as she came, trembling, in the midst of all of them. The tentacles didn’t slow for a long few seconds and she gratefully squirmed at their heart, soaking up every second of ecstasy she could.

No sensation registered beyond the five, her hands, her mouth, and the most intimate parts of her filled by Kara’s tentacles.

When she opened her eyes, Kara was leaning close to peer at her.

“Wow,” Kara said softly.

“Mm?” Alex said, tentacle still in her throat.

“Humans cum so easily,” Kara said. “Are you… do you think you can manage more? I, uh, still need a bit to…”

Only Kara could seem so shy while pushing a tentacle up Alex’s ass. Alex nodded, not even caring if she looked desperate.

And then the tentacles began moving again, all of them guiding and holding each part of Alex’s body, even the parts that weren’t inside her squirming and reminding Alex of their presence.

For a moment it seemed like Kara was going to lift her up, though she relented, content instead simply to have Alex lie on her back on the bed while she felt what seemed like dozens of limbs wrap around her and dedicate every effort to making her feel as good as possible.

“Wow, Alex,” Kara gasped. “That’s incredible, you’re incredible, oh Rao…”

Her murmurings dissolved into kryptonese that Alex suspected would be bordering on incoherent even if she understood the language.

She wasn’t sure how many times she came. Even bordering on blissed out though, she didn’t miss it when Kara did; she felt the tentacles suddenly convulse, she heard a low groan turn into a shuddering gasp like Kara had run into a wall, and felt a sudden heat suffuse her. The tentacles still moved almost leisurely for some minutes after that, still filling her.

And then they withdrew, leaving Alex slumped back on the bed, breathless and aching and not sure if she was sore from how thoroughly she’d been fucked or just plain aching for them to return.

Ok, new kink. To say nothing of the thinnest tentacle receding, unwinding as it journeyed back down her leg. She’d learned a lot of new things about herself.

Alex took in a deep, long breath.

“Wow,” Kara said.

Alex shifted, not quite sitting up but propping herself up with her elbows to look down the bed. Kara had collapsed too, on her side, still facing Alex.

The last of the tentacles slid back out of view. Alex opened her mouth to speak, and instead slumped back down to the bed, drained.

Wow was right.

“Thank you,” Kara said. “That… I feel better. _So much_ better. You, uh, won’t need to do that again, but… wow. That was really…”

“Mm,” Alex managed.

For god’s sake, she was still dressed. She’d just had a chain of the best orgasms of her entire life, one after another, from her tentacle-wielding sister. It felt like she should be having much more of a reaction!

Instead it was hard to do anything more than bask.

Holy fuck.

She just about twitched her leg. Ok. Her body still worked, even if it was tingling, legs still shaking from what might as well have been the hundredth time she’d cum.

“Kara,” Alex managed, slightly hoarse.

Somehow she had the feeling she’d be thinking about today a lot.

“Yeah?” Kara said.

“If you do… ever need… again,” Alex said. “Just ask. _Please_.”

Kara’s eyes lit up.

“And don’t tell mom,” Alex said. “Let’s just… mm… say you were worried about school, ok?”

“Ok!” Kara said.

Alex took a breath. It was a few moments before she felt able to sit up.

“So,” Alex said slowly. “You’ll have to do that again in a few years?”

* * *

Alex waited at the doorway of Kara’s apartment, trying to get her breathing under control. Damn it, she was a grown woman!

Still, it had been a few years. A few years in which Kara had started being a superhero, in which she’d realised she did legitimately like women and it wasn’t just because men compared poorly to tentacles, in which Kara had been fine even if she still hadn’t found anyone to be completely open with.

There had been a couple of people, but by the sound of it they’d freaked a little at the first sight of a tentacle.

Part of Alex burned at that. She wasn’t sure how much was jealousy and how much was sympathy; Kara deserved better, she deserved someone. And Alex knew she wanted it to be her, even if it was… inappropriate.

She knocked on Kara’s door, taking a breath.

It had been years, and Kara had let slip in a slightly awkward phone call that it was beginning to be too much again. Alex was probably the only person on the planet that knew all the details of what Kara needed.

She was definitely the most excited. She liked Kara for so many reasons, but she wasn’t going to pretend Kara hadn’t singlehandedly given her a whole host of kinks back in Midvale.

It was hard to not look forward to it.

Slightly flustered, Kara opened the door. Alex quickly crossed the threshold.

The curtains were shut, Alex noted, as Kara closed the door behind her. Probably smart, she wouldn’t want to be glimpsed through the windows at the best of times, and tonight she _definitely_ didn’t.

“So, how do we…” Alex began.

She turned. Wriggling, squirming tentacles were already sliding out of Kara’s pants. Huh, Alex reflected, Kara had been right. Kryptonians _did_ grow more as they got older.


End file.
